const jwt = require("jsonwebtoken")
const utils = require("../modules/utils")
const bcrypt = require("bcryptjs")
const crypto = require("node:crypto")
const authRepository = require("../repositories/authRepository")
const certsManager = require("../modules/certificatesManager")
const { DefaultError } = require("../errors/errors")

const keys = certsManager.getKeys()
const uuidRegex = /^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}$/

async function registerUser({ username, password, email, registrationCountry, preferredLanguage, clientIp }) {
    try {
        await authRepository.getUser(username)
        throw new DefaultError(409, "Username taken.", "ForbiddenOperationException")
    } catch (error) {
        if (error.code !== 404) throw error
    }

    if (email) {
        try {
            await authRepository.getUser(email)
            throw new DefaultError(409, "E-Mail taken.", "ForbiddenOperationException")
        } catch (error) {
            if (error.code !== 404) throw error
        }
    }

    const userRegistration = await authRepository.register(email || "", username, password)
    const { uuid } = userRegistration

    const resolvedCountry = registrationCountry || await utils.getRegistrationCountryFromIp(clientIp)
    await authRepository.addPropertyToPlayer("registrationCountry", resolvedCountry || "UNKNOWN", uuid)
    await authRepository.addPropertyToPlayer("userPreferredLanguage", preferredLanguage || "fr-FR", uuid)

    return { code: 200, message: "User created successfully", uuid }
}

async function authenticate({ identifier, password, clientToken, requireUser }) {
    let userResult
    
    try {
        userResult = await authRepository.getUser(identifier, true)
    } catch (error) {
        if (error.code === 404) {
            throw new DefaultError(403, "Invalid credentials. Invalid username or password.", "ForbiddenOperationException")
        }
        throw error
    }

    const passwordValidationProcess = await bcrypt.compare(password, userResult.user.password)
    if (!passwordValidationProcess) {
        throw new DefaultError(403, "Invalid credentials. Invalid username or password.", "ForbiddenOperationException")
    }

    delete userResult.user.password

    const $clientToken = uuidRegex.test(clientToken) ? clientToken : crypto.randomUUID()
    const accessToken = jwt.sign({
        uuid: userResult.user.uuid,
        username: userResult.user.username,
        clientToken: $clientToken,
    }, keys.authenticationKeys.private, { 
        subject: userResult.user.uuid, 
        issuer: "LentiaYggdrasil", 
        expiresIn: "1d", 
        algorithm: "RS256" 
    })

    const clientSessionProcess = await authRepository.insertClientSession(accessToken, $clientToken, userResult.user.uuid)

    const userObject = {
        clientToken: clientSessionProcess.clientToken,
        accessToken: clientSessionProcess.accessToken,
        availableProfiles: [{
            name: userResult.user.username,
            id: userResult.user.uuid,
        }],
        selectedProfile: {
            name: userResult.user.username,
            id: userResult.user.uuid,
        }
    }

    if (requireUser) {
        try {
            const propertiesRequest = await authRepository.getPlayerProperties(userResult.user.uuid)
            userObject.user = {
                username: userResult.user.username,
                properties: propertiesRequest.properties
            }
        } catch (error) {
            if (error.code !== 404) throw error
            userObject.user = {
                username: userResult.user.username,
                properties: []
            }
        }
    }

    return {
        code: 200,
        response: userObject
    }
}

async function refreshToken({ previousAccessToken, clientToken, requireUser }) {
    let sessionCheck
    try {
        sessionCheck = await authRepository.getClientSession(previousAccessToken, clientToken)
    } catch (error) {
        throw new DefaultError(403, "Invalid token or session expired.", "ForbiddenOperationException")
    }

    const uuid = sessionCheck.session.uuid

    const userResult = await authRepository.getUser(uuid, true)
    delete userResult.user.password

    await authRepository.invalidateClientSession(previousAccessToken, clientToken)

    const $clientToken = uuidRegex.test(clientToken) ? clientToken : crypto.randomUUID()
    const newAccessToken = jwt.sign({
        uuid: userResult.user.uuid,
        username: userResult.user.username,
        clientToken: $clientToken,
    }, keys.authenticationKeys.private, { 
        subject: userResult.user.uuid, 
        issuer: "LentiaYggdrasil", 
        expiresIn: "1d", 
        algorithm: "RS256" 
    })

    const clientSessionProcess = await authRepository.insertClientSession(newAccessToken, $clientToken, userResult.user.uuid)

    const userObject = {
        clientToken: clientSessionProcess.clientToken,
        accessToken: clientSessionProcess.accessToken,
        selectedProfile: {
            name: userResult.user.username,
            id: userResult.user.uuid,
        }
    }

    if (requireUser) {
        try {
            const propertiesRequest = await authRepository.getPlayerProperties(userResult.user.uuid)
            userObject.user = {
                username: userResult.user.username,
                properties: propertiesRequest.properties
            }
        } catch (error) {
            if (error.code !== 404) throw error
            userObject.user = {
                username: userResult.user.username,
                properties: []
            }
        }
    }

    return {
        code: 200,
        response: userObject
    }
}

async function validate({ accessToken, clientToken }) {
    if (clientToken !== undefined) {
        await authRepository.validateClientSession(accessToken, clientToken)
    } else {
        await authRepository.validateClientSessionWithoutClientToken(accessToken)
    }
    return { code: 204 }
}

async function invalidate({ accessToken, clientToken }) {
    await authRepository.invalidateClientSession(accessToken, clientToken)
    return { code: 204 }
}

async function signout({ uuid }) {
    await authRepository.revokeAccessTokens(uuid)
    return { code: 204 }
}

async function verifyAccessToken({ accessToken }) {
    try {
        if (!accessToken) {
            throw new DefaultError(400, "Token is missing.")
        }

        const decoded = jwt.verify(accessToken, keys.authenticationKeys.public, {
            algorithms: ["RS256"],
            issuer: "LentiaYggdrasil"
        })

        const clientToken = decoded.clientToken
        if (!clientToken) {
            throw new DefaultError(403, "Token format invalid (missing clientToken).")
        }

        try {
            await authRepository.validateClientSession(accessToken, clientToken)
        } catch (error) {
            throw new DefaultError(401, "Session has been revoked or invalidated.")
        }

        return { 
            code: 200,
            user: {
                uuid: decoded.sub,
                username: decoded.username
            },
            session: {
                clientToken
            }
        }

    } catch (error) {
        if (error instanceof DefaultError) throw error
        
        if (error.name === "TokenExpiredError") {
            throw new DefaultError(401, "Token has expired.")
        }
        throw new DefaultError(500, "Internal Verification Error", error.toString())
    }
}

module.exports = {
    signout,
    validate,
    invalidate,
    registerUser,
    authenticate,
    refreshToken,
    verifyAccessToken,
}